Electromagnetic device



April 23, 1935. B. E. GETC HELL ELECTROMAGN TIC DEVICE Original FiledJan. 15, 1930 2 Sheets-Sheet 1 April 23, 1935. B. E. GETCHELL 0ELECTROMAGNETIC DEVICE I 7 Original Filed-Jan. 15, 1930 2 Sheets-Sheet 2INVENTOR BENJAMIN E. ETOHELL,

Patented Apr. 23, 1935 I UNITED STATES PATENT OFFICE mcraomcnaric DEVICEI Benjamin a. Getchell, Plainville, Conm, assignor to The TrumbullElectric Manuiacturing Compfi, 1;lainville, Conn. a corporation of Connon Original application January 15, 1930, Serial No. 420,929. Dividedand this application November 19, 1932, Serial No. 643,317

6 Claims. (01. 175-330) My invention relates to magnetically operatedvide means to allow the normally stationary switches and particularly toan electro-magnet member of the magnet to recede to a limitedconstruction which is specially adapted for use extent to check theimpact of the movable memin connection with switch constructions similarher in response to a greater impact than can be to-the type disclosed inmy Patent No. 1,714,085. absorbed by the magnetic braking grip betweenThis application is a division of my application the armature and thecore of the magnet. Serial No. 420,929, filed January 15,1930,; issuedAnother object is to provide an operable elecas Patent No. 1,893,827 onJanuary 10, 1933. tro-magnet in which one of the movable mem-Electro-magnetic switchesvof the type referred bers oi the magnet .mayhave a lost-motion conll') to. are necessarily made up of acomparatively nection with a movable switch member or a 10 large numberof parts including stationary and similarly operated device so that themovement movable contacts, connectors, bolts, screws, etc., of the partto be pe l not begin until and the hammer-like blows of an ordinaryelecthe operating part of the magnet has already 4 tro-magnet in thecircuit closing movement tends attained substantially full speed in itsoperating to loosen some of these parts to aserious extent movement. 15especially when the magnet is rigidly connected Another object is toprovide an electro-magto the movable switch contacts or is mounted neticopera mechanism which ay be made, directly on; the switch base or on apart of the assembled and opera y tested ndep nd ly f enclosing box. thedevice which it is intended to operate and The principal object of myinvention is to pro which may readily and operably be connected 20 videan electro-magnet construction suitable for to or disconnected from thedevice. use in operating switches of the type referred Another object isto provide an electro-magto, or other. similar devices, and which may benetically operated switch construction in which associated with suchdevices and operated with the switch, including'all of its directlyrelated considerable 'force without transmitting any parts, may beassembled as aunit and in which 25 harmful shock to itself or to thedevice to be the electro-magnet, including all ofits directly operatedor to the enclosure in which the conrelated parts, may beassembled asanother instruction is housed. I dependent unit and in which the switchunit and Another object is to provide an electro-magnet the magnet unitmay be readily connected for unit having an armature and a magnetconsistservice or use. l

ing of a coil and a core, the core having one or In carrying out theinvention in its preferred mOre armature ing legs and in which conform Iprovide switch mechanism having stastruction, the "parts are so mountedand co-retionary and movable contacts supported by an lated that theoperating force or impact will be insulating body, the parts beingconstructed and absorbed by the members of the unit without assembled asa unit. I also provide an electro- 35 transmitting any harmiul shock tothe other asmagnetic actuating member which is constructed SociatedPart5 d ces. and assembled as an independentnunit. Both of Anotherobject isto provide an electro-magnet the units are supported by acommon plate-and construction in which the armature and the mag-- are sorelatedthat, when installed for service, 40 net with its core areindependently and pivotally gravitytends to hold the parts of the switchand 40 a mounted with their respective axial centers the parts of theelectro-magnetic mechanism in spaced soiar apart that when thearmatureen-' the open circuit or Oil position. .The electrogages the core of themagnet or vlce-versa, it magnetic device for actuating the switch properwill be with a pivotal motion and also with 9. includes a pivoted orhinged core member and an 46 sliding or surface wi-p movement as soon-asindependently pivoted or hinged armature memthe parts have comeintocontact witheach ber. Both of-these members are so mounted as oth Y.I to tiltforwardly at their upper ends away from Another object is toprovide an electro-magnet the back'plate n a l i in their w ngconstruction in which, in the circuit closing movements by suitablestops. They are so conmagnet will engage with a sliding surface actionture member first moves rearwardly towards-the in such a manner that theoperating shock or core member which, by reason of its stop, reimpactwill be'partly absorbed by the magnetic mains stationary until thearmature actually grip between the armature and the core of the strikesit with all of its momentum less the magmovement, the armature and thecore ,of the 'structed that when the circuit is closed the arms.- 50

magnet and a directly related object is topronetic braking torce causedby the sliding or wiping engagement of the armature and the core andwhich wiping engagement is due to the fact that the armature and thecore are pivoted at spaced apart axial centers. When the magnet istie-energized, the core remains stationary by' reason of its stop butthe armature swings forwardly to the open circuit position and, byreason] of its connections, simultaneously moves the switch contactsinto the Off position.

Fig. 1 is a front view showing a switch with the electro-magneticactuator.

Fig. 2 is an exploded perspective view of the parts of theelectro-magnetic device.

Fig. 3 is a view of the right hand side of the net take when thearmature strikes the magnet.

Fig. 6 is a plan view showing a fragment of the switch with the magneticelements.

In the prefered form of construction the stationary and movable parts ofthe switch mechanism as well as the actuating mechanism are allsupported directly or indirectly by a back plate II] which is adapted tobe suitably secured in a vertical position when in service and usuallyin an enclosing or protecting box or receptacle.

A body member I I formed preferably of molded insulation is secured inany suitable manner to the side plates I2 and I3 which in turn aresecured to the back plate, for instance, by screws such as I4.

The switch illustrated is for a three-wire system but so far as theinvention herein claimed is concerned the number of switching unitsembodied in the construction is immaterial. It will therefore benecessary to describe only the units necessary for controlling a singlecircuit. The line terminal I6 is connected to the stationary switchcontact I! and suitably anchored to the insulating body. The lowerstationary switch contact I8 is connected in a suitable manner with thelower load terminal I9. The front view of two stationary contacts I1 andI8. similar to contacts I! and I8, is shown at the left of Fig. l. Themovable contact member is slidably supported on a stud 2| which iscarried by the insulating cross bar 22 which is interposed between theupper and lower stationary contacts. Each movable switch member isprovided with a resilient abutment spring 23 interposed between thereinforcing member '24 and the washer 25. The insulating cross bar 22 isprovided with projecting lugs 26 which are guided in inclined slots 21formed in the side plates I2 and I3 respectively. When the parts aresupported in their normal manner gravity tends to hold the cross bar 22and all of the attached switch members in the open circuit position.

. A crank shaft 30 is pivotally supported in the side plates I2 and I3and has crank arms 3| hinged to the links 32.which in turn are connectedto' the lugs 2Gjwhich project from the opposite ends of the cross bar22. The crank shaft 3!! also has an elongated arm 33 which extendslaterally through an opening in the side plate I3 to facilitateconnection with operating I means. When the arm 33 is pressed rearwardlythe crank shaft 30 turns on its axis and draws the two links 32 and theattached cross bar 22 rearwardly. In this movement the movable switchcontacts 20 engage the stationary switch contacts I! and I8. Astherotation of the crank shaft is continued the cross bar 22 movesfurther rearwardly carrying with it the studs 2| which draw the washersand the springs 23 to provide increased pressure 5 on the movable switchmembers. When pressure on the crank shaft is released gravity tends A tobring the movable switch members and the supporting cross bar outwardlyto break the circuit. This movement is accelerated by the ac- 10 tion ofthe springs 23 so as to ensure a prompt and effective breaking of thecircuits through the respective switch units.

back plate Ill by screws such as 35. The magnet core is of suitableconstruction and in the pre- 25 ferred form has the three legs 38 and 38and 39.

In the form shown the core is laminated and provided with side bars 40all riveted or otherwise suitably secured together. The lower ends ofthese side bars are hinged to a pin H which is supported in the postmembers 31. The swinging movement of the magnet core is limited at theupper end in the forward direction by the lugs 42 which act as abutmentsfor the outer ends of the side bars 40. The back plate serves as 35 anabutment to limit the rearward movement of the magnet core. The locationof the parts is such that the weight of the core together with theweight of the coil 43 tends to swing and to hold the magnet coreforwardly. The coil is suitably connected in circuit to be controlledmanually or automatically in any suitable manner.

The armature member also includes a channellike carrier 44 having arms45 hinged to a pin 46 5 carried by the outer ends of the posts 31independently of the hinging of the core member. The armature bar 41 isloosely carried by a hinge .pin 48 between the flanges 49 of the carrierso that the armature is free to adjust itself to the 5 faces of thecore. A link 50 has its rear end detachably hinged to the arm 33 of thecrank shaft 30 and has-its front end provided with a lost motion meansof connection with the upper end of the armature member.

This connection is affected by a pin 5| carried by the lugs 52 andslidable in the-slot 53. The outer end of the link 50 is looselypositioned between fingers 54 at the upper end of the armature carrier.The parts of the armature are. so 0 disposed as to bring its entireweight forward of the hinge pin 46 so that gravity tends to swing thearmature and to hold it in the open circuit or Off position in the sameway that gravity tends to-hold the magnetic core member forwardly.

When the magnet is energized either by local or remote control of itscircuit the armature is of course drawn toward the core member. Duringthe first part of its movement-the magnet has to move'only the armaturemember but as 70 soon as the pin 5| strikes the rear end'of the slot 53in the switch connecting link 54,- themagnet tends to rock the crankshaft 3| and move the switch members to the'closed circuit position. Thefirst resistance met (other thanithe resistance. 78

core so securely with a frictional braking action that the magnet framewill not be forced to any great extent away from its position with itsside bars 40, 40 at rest against the stop lugs 42, 42.

Because of the fact that the armature frame and the magnet frame arepivoted at spaced apart axial centers, it is obvious that after thearmature and the magnet core have been brought together, any furtherrotary movement of the parts in the circuit closing direction will causea wiping or sliding engagement between the face of the armature and thecontacting surface of the legs of the magnet core. It is also obviousthat the strength of the magnet will constantly increase from the momentthe armature begins to move until, just before the armature actuallymakes contact with the core of the magnet, it will be at substantiallyits full strength and ready to brake or prevent any sliding movement ofthe engaging portions of the magnet numbers after they have been movedinto actual-contact; under some conditions however, the impact of thearmature may be great enough to overcome-the braking force of the magnetand may force the frame of the magnet backwardly away from its stop lugs42, 42 and, I have provided means for this to occur without transmittingany -appre-- ciable shock to the switch or is being operated.

The side bars 40, 40, which carry the magnet with its core are pivotedat their lower ends to the post members 31', 31 and the upper ends ofthe bars 40, 40 are free to swing between the stop lugs 42, 42 and theback plate 35. Normally the upper ends .of the side bars 40; 40 restagainst the stop lugs 42, 42 but in case of an excessive impact ofthearmature in striking against the core of the magnet the magnet partof the unit is free to swing back towards the base plate and thus absorbthe excessive momentum of the armature.

In some cases the core of the magnet may remain in this receded positiondue to the frictional resistance in which event the spring 23 will exertmore pressure against the movable contacts to hold them more rigidly inthe On position but, while this is desirable, it is not necessary sincethe construction is designed so that while normally, the, core portionof the magnet may recede slightly. in response to the other device whichimpact of the armature, it will return to its posi-.

tion with the upper ends of the side resting against the stop lugs 42,42.

When the electro-magnetic circuit is deenergized either intentially orautomatically, the armature is of course released and swings or fallsaway from the core by gravity and its weight tends topullthe links 50and attached members outwardly. The lost motion connection of the pin Siin the slots 53 allows the bars 40, 40

- armature to have a certain freedom of -movement so that when itisreleased and starts to move it is substantially free of the link 50and attached parts and thus is able to obtain considerable momentumwithout the resistance of the other parts and before it hasstarted tomove .thecontacts to the open circuit or Off position.

By this construction a hammer-like blow is given to the cross bar 22 inthe opening movement of the switch which prevents the contacts or otherparts from sticking. The loose pivoting of the armature" in its carrierframe permits it to adjust itself to the core of the magnet and thusovercome any difllculty due to irregularities in mechanical constructionand at the same time ensures the maximum strength of the magnetic field.Also, by means of the lost-motion connection between the armature andthe connecting link 50, the armature does not start the movement of theswitch contacts until pin 5| reaches the other end of the slot 53 in thelink 50 and by this time the armature has attained sumcient speed ofmovement to cause a very quick-make action of the movable switchcontacts.

I claim:

1. An electro-magnetic switch actuator including a supporting frame,anelectro-magnetic core hinged at its lower end to said frame and havingits weight so disposed as to swing outwardly at its upper end away fromsaid frame, an armature hinged at its lower end to said frame andmovable independently of the core, means for limiting the forwardtilting movement of the core and means for limiting the forward tiltingmovement of the armature, said core being tiltable toward the rear withthe armature so as by its inertia at least partially to absorb momentumof the armature toward the core, the pivotal centers of said magneticcore and of said armature being spaced apart for the purpose specified.

2. An electro-magnetic switch actuator including a channel-likesupporting frame, an electromagnetic core hinged at its lower end insideof said frame and having its weight so disposed as to hang outwardly at.its upper end away from said frame, an armature hinged at its lower endto said frame and movable independently of and also with the core, meansfor limiting the forward tilting movement of the core and means forlimiting the forward tilting movement of the armature, said core beingtiltable toward the rear with the armature, the armature and the magnetcore being movable together rearwardly when the magnet is energized andthe armature strikes ters so that the core of the magnet will yieldinglycheck the operating impact of said armature and the magnetic grip ofsaid armature and said magnet will check further axial movement of saidarmature.

4. An electro-magnet including a magnet core and coil, an armaturepivotally supported atits lowe'rend and adapted to coact with said core,a stop for limiting the movement of the core toward the armature, thearmature being free to move toward the core, a pivotal support for themagnet core spaced apart; from the pivotal axis of the armature so thatthe'core of the magnet will check the momentum oi the armature and themagnetic force between the magnet and the armature produces frictionsuflicient to retard the action of the armature with respect tothe'core. 5. A switch actuating electro-magnet constplction comprising acore having an energizing coil and pivoted at its lower end near therear so that ing a core and a coil hinged at its lower end with itscenter of gravity disposed in front of the hinged center, a stopnormally limiting the forward swinging movement of the core and coil, anarmature coacting with the core and hinged on an axis spaced apart fromthe hinged axis of the core and means to be actuated by the movement ofthe armature and having a lost motion connection therewith.

BENJAMIN E. GETCHELL.

